The invention relates to a piston pump for a high-pressure cleaning appliance, comprising a pump block having a plurality of pump chambers, into each of which one piston which is movable back and forth parallel to a longitudinal pump axis plunges, and comprising a pump head fitted on the pump block and having a suction inlet for supplying liquid and a pressure outlet for discharging liquid, each pump chamber being in flow connection via a suction valve with the suction inlet and via a pressure valve with the pressure outlet, and comprising a clamping bracket engaging around the pump head for clamping the pump head to the pump block.
By means of such piston pumps, a liquid, preferably water, can be pressurized and delivered via a pressure hose to a discharge device, for example, a spray lance or spray nozzle. This makes it possible to direct the pressurized liquid onto an article or a surface in order to clean the article or the surface. The pressure of the liquid may be significantly more than 100 bar. Therefore, the piston pump must have a considerable degree of mechanical stability. On the other hand, it should be possible to produce and assemble the piston pump as cost-effectively as possible. In DE 195 48 498 A1, it is, therefore, proposed that the pump head be produced from a plastic material and clamped by means of a clamping element to the pump block. In this case, the clamping element is constructed as a hood with a large number of bridges extending at an incline to the longitudinal pump axis, and with a connection pipe into which the pressure outlet of the pump head, which is constructed as pressure connection piece, extends. In addition, the clamping element comprises a support flange which lies against a step of the pressure connection piece and from which the bridges extend at an incline to the longitudinal pump axis in the direction of the pump block. The clamping element, therefore, has an elaborate construction which involves not inconsiderable production costs. During assembly of the piston pump, care must be taken to ensure that the support flange of the clamping element lies with surface-to-surface contact on the corresponding step of the pressure connection piece of the pump head.
A piston pump of the kind mentioned at the outset is proposed in DE 195 59 336 C1. In this piston pump, use is made of a clamping element with two U-shaped clamping brackets which are connected to each other by a rigid connecting part. The connecting part has a through-bore through which the pressure connection piece passes. The two U-shaped clamping brackets each have two limbs, which are connected to each other by a bridge. The bridges of the clamping brackets lie offset from the longitudinal pump axis in each case against the end face of the pump head.
There is known from WO 2008/128591 A1 a piston pump, in which the pump head has tension rods which extend over the pump block in the axial direction and are releasably connectable to a pump drive, the pump block being clamped between the pump head and the pump drive. In this piston pump, a separate clamping element can be dispensed with. Instead, a pump head with a special shape is used.
The object of the present invention is to develop a piston pump of the kind mentioned at the outset in such a way that it can be produced more cost-effectively and assembled more easily.